This medication is used to treat a certain nervous system disorder that can lead to muscle weakness and muscle loss (spinal muscular atrophy). Onasemnogene abeparvovec is made from a certain virus that has been specially prepared. The virus is used to carry a certain human gene into cells. This type of treatment is known as gene therapy. Treatment may improve motor function.

This medication is given by slow injection into a vein as directed by the doctor. It is given as a single dose. The dosage is based on your child's body weight.

Small amounts of virus may shed from the child's stool for up to 1 month after the injection. Ask the doctor how to handle and dispose of waste materials (such as diapers) for up to 1 month after the injection.

See also Warning section.

Vomiting may occur. If this effect lasts or gets worse, tell the doctor or pharmacist promptly.

Remember that this medication has been prescribed because the doctor has judged that the benefit to your child is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell the doctor right away if your child has any serious side effects, including:

• easy bleeding/bruising
• signs of kidney problems (such as change in the amount of urine)

Get medical help right away if your child has any very serious side effects, including:

• seizures

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before this medication is given, tell the doctor or pharmacist if your child has any allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to the pharmacist for more details.

Before using this medication, tell the doctor or pharmacist your child's medical history, especially of:

• liver problems (including cirrhosis, fatty liver disease, hepatitis B or C)
• current/recent infection

Onasemnogene abeparvovec may make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to the doctor if your child has been exposed to an infection or for more details.

Tell the health care professional that your child has received this medication before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

Before having surgery, tell the doctor or dentist about all the products your child uses (including prescription drugs, nonprescription drugs, and herbal products).

This medication is not usually used by adults. It is unlikely to be used during pregnancy or breastfeeding. Consult your doctor if you have any questions about this medication.

Drug interactions may change how your child's medications work or increase the risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with the doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without the doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as liver function, complete blood count) must be done before your child starts receiving this medication and after your child receives it. Keep all medical and lab appointments.

After receiving this treatment, your child cannot donate blood, organs, tissues, or cells.

Not applicable.

Not applicable. This type of product is given in a hospital or clinic and will not be stored at home.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).